Doors of the type used for closing a large opening in a building, such as a garage door, have long been manufactured using a plurality of substantially identical panels. The plurality of panels are typically hingedly or pivotally connected together to permit relative hinging movement between adjacent panels when the door is moved between a closed vertical position in which the panels are aligned, an intermediate position in which the panels are hinged at an angle to each other, and an open horizontal position.
Such multi-panel doors are commonly referred to as sectional doors and often employ thin sheet material, such as metal, fiberglass, or plastic, and an insulating core to form each panel of the multi-panel door. Thus, the individual panels are light in weight and highly warp-resistant over relatively long spans of time. However, due to the composite construction of such panels, multi-panel doors often lack sufficient structural strength and/or do not provide sufficient thermal and electrical insulation between adjacent panels, and between the door and the outside environment.